set screw on nikkor sw 90/8

[james norman]

the back side of the copal #0 shutter on my nikkor sw 90/8 (the surface which re sts immediately adjacent to the lens board) is presenting an odd problem in moun ting the lens. on the back side of the shutter, you can see the control ring fo r the aperture adjustment. this ring is held in place by a smaller ring with th ree small screws - this smaller ring also serves to offset the lens from the len s board by a small amount to allow for movement of the aperture adjustment. how ever, also present in this outer ring is a small set screw which extends out fro m the ring and will not allow me to mount the lens flush with the lens board. w hat is this set screw for, and why does it stick out like this? what is the sol ution? thanks.

[mark eban]

This is an alignment screw. For the seriously anal, you drill a small depression (but not a hole) in your lensboard, just deep enough to accomadate the screw head. This stops any slippage even if your locking ring loosens. In my view the sensible thing to do is (a) unscrew it (b) throw it away (c) mount to the lensboard in the normal fashion. It serves no other function in retaining any part of the lens mounting.

[James Chow]

Right, the salesman at Yodobashi Camera told me it was because the Nikon lens boards have the alignment hole pre-drilled.